bisecting fixing commit since e99332e7b4cda6e60f5b5916cf9943a79dbef902 building syzkaller on 8742a2b9dba1ce2869b29fff6c5359cc9116c719 testing commit e99332e7b4cda6e60f5b5916cf9943a79dbef902 with gcc (GCC) 8.1.0 kernel signature: d9ba8d45c3b82c5163499472201d84ec6753b87db8ab85600f390a4aa7d2bd43 run #0: crashed: INFO: task hung in do_read_cache_page run #1: crashed: INFO: task hung in blkdev_put run #2: crashed: INFO: task hung in blkdev_put run #3: crashed: INFO: task hung in do_read_cache_page run #4: crashed: INFO: task hung in blkdev_put run #5: crashed: INFO: task hung in blkdev_put run #6: crashed: INFO: task hung in blkdev_put run #7: crashed: INFO: task hung in blkdev_put run #8: crashed: INFO: task hung in do_read_cache_page run #9: crashed: INFO: task hung in blkdev_put testing current HEAD 713eee84720e6525bc5b65954c5087604a15f5e8 testing commit 713eee84720e6525bc5b65954c5087604a15f5e8 with gcc (GCC) 8.1.0 kernel signature: db641029d777ad4d6d5bcfc217eba0a7f72733dd21c93436f90270346aeda489 run #0: crashed: INFO: task hung in do_read_cache_page run #1: crashed: INFO: task hung in blkdev_put run #2: crashed: INFO: task hung in blkdev_put run #3: crashed: INFO: task hung in do_read_cache_page run #4: crashed: INFO: task hung in do_read_cache_page run #5: crashed: INFO: task hung in blkdev_put run #6: crashed: INFO: task hung in do_read_cache_page run #7: crashed: INFO: task hung in do_read_cache_page run #8: crashed: INFO: task hung in do_read_cache_page run #9: crashed: INFO: task hung in do_read_cache_page revisions tested: 2, total time: 22m43.395111612s (build: 10m30.782769452s, test: 11m38.88185786s) the crash still happens on HEAD commit msg: Merge tag 'perf-tools-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux crash: INFO: task hung in do_read_cache_page INFO: task systemd-udevd:8306 blocked for more than 143 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-udevd state:D stack:13568 pid: 8306 ppid: 3916 flags:0x00004100 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x3f3/0x880 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 io_schedule+0xd/0x40 kernel/sched/core.c:6296 wait_on_page_bit_common+0x258/0x350 mm/filemap.c:1191 wait_on_page_bit mm/filemap.c:1216 [inline] wait_on_page_locked include/linux/pagemap.h:611 [inline] wait_on_page_read mm/filemap.c:2833 [inline] do_read_cache_page+0x275/0x3f0 mm/filemap.c:2876 read_mapping_page include/linux/pagemap.h:437 [inline] read_part_sector+0x31/0x13e block/partitions/core.c:770 adfspart_check_ICS+0x2d/0x3a0 block/partitions/acorn.c:360 check_partition block/partitions/core.c:140 [inline] blk_add_partitions+0x160/0x400 block/partitions/core.c:698 bdev_disk_changed+0x6e/0xf0 fs/block_dev.c:1416 __blkdev_get+0x36e/0x730 fs/block_dev.c:1559 blkdev_get+0xf/0x30 fs/block_dev.c:1639 do_dentry_open+0x15a/0x3c0 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x47d/0xa90 fs/namei.c:3368 do_filp_open+0x8e/0x100 fs/namei.c:3395 do_sys_openat2+0x219/0x2d0 fs/open.c:1168 do_sys_open+0x46/0x80 fs/open.c:1184 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f65955f5840 Code: Bad RIP value. RSP: 002b:00007ffe02e17a98 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000055a9c69737c0 RCX: 00007f65955f5840 RDX: 000055a9c51b5fe3 RSI: 00000000000a0800 RDI: 000055a9c698ea50 RBP: 00007ffe02e17c10 R08: 000055a9c51b5670 R09: 0000000000000010 R10: 000055a9c51b5d0c R11: 0000000000000246 R12: 00007ffe02e17b60 R13: 000055a9c6987e00 R14: 0000000000000003 R15: 000000000000000e INFO: task systemd-udevd:8311 blocked for more than 143 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-udevd state:D stack:13568 pid: 8311 ppid: 3916 flags:0x00004100 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x3f3/0x880 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 io_schedule+0xd/0x40 kernel/sched/core.c:6296 wait_on_page_bit_common+0x258/0x350 mm/filemap.c:1191 wait_on_page_bit mm/filemap.c:1216 [inline] wait_on_page_locked include/linux/pagemap.h:611 [inline] wait_on_page_read mm/filemap.c:2833 [inline] do_read_cache_page+0x275/0x3f0 mm/filemap.c:2876 read_mapping_page include/linux/pagemap.h:437 [inline] read_part_sector+0x31/0x13e block/partitions/core.c:770 adfspart_check_ICS+0x2d/0x3a0 block/partitions/acorn.c:360 check_partition block/partitions/core.c:140 [inline] blk_add_partitions+0x160/0x400 block/partitions/core.c:698 bdev_disk_changed+0x6e/0xf0 fs/block_dev.c:1416 __blkdev_get+0x36e/0x730 fs/block_dev.c:1559 blkdev_get+0xf/0x30 fs/block_dev.c:1639 do_dentry_open+0x15a/0x3c0 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x47d/0xa90 fs/namei.c:3368 do_filp_open+0x8e/0x100 fs/namei.c:3395 do_sys_openat2+0x219/0x2d0 fs/open.c:1168 do_sys_open+0x46/0x80 fs/open.c:1184 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f65955f5840 Code: Bad RIP value. RSP: 002b:00007ffe02e18088 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000055a9c69737c0 RCX: 00007f65955f5840 RDX: 000055a9c51b5fe3 RSI: 00000000000a0800 RDI: 000055a9c6975e70 RBP: 00007ffe02e18200 R08: 000055a9c51b5670 R09: 0000000000000010 R10: 000055a9c51b5d0c R11: 0000000000000246 R12: 00007ffe02e18150 R13: 000055a9c69619c0 R14: 0000000000000003 R15: 000000000000000e INFO: task syz-executor.4:20055 blocked for more than 143 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:14072 pid:20055 ppid: 7009 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x3f3/0x880 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103 blkdev_put+0x18/0x130 fs/block_dev.c:1804 blkdev_close+0x1f/0x30 fs/block_dev.c:1853 __fput+0xaa/0x250 fs/file_table.c:281 task_work_run+0x68/0xb0 kernel/task_work.c:135 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:139 [inline] exit_to_user_mode_prepare+0x1e2/0x1f0 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c8a9 Code: Bad RIP value. RSP: 002b:00007f25185f6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00000000004e8ea0 RCX: 000000000045c8a9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000409 R14: 00000000004c6ae4 R15: 00007f25185f76d4 INFO: task syz-executor.4:20077 blocked for more than 143 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:14176 pid:20077 ppid: 7009 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x3f3/0x880 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103 __blkdev_get+0xf2/0x730 fs/block_dev.c:1492 blkdev_get+0xf/0x30 fs/block_dev.c:1639 do_dentry_open+0x15a/0x3c0 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x47d/0xa90 fs/namei.c:3368 do_filp_open+0x8e/0x100 fs/namei.c:3395 do_sys_openat2+0x219/0x2d0 fs/open.c:1168 do_sys_open+0x46/0x80 fs/open.c:1184 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x416621 Code: Bad RIP value. RSP: 002b:00007f25185d57a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000416621 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f25185d5850 RBP: 000000000078bfa0 R08: 000000000000000f R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000c0f R14: 00000000004ce41d R15: 00007f25185d66d4 INFO: task syz-executor.0:20086 blocked for more than 144 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:14408 pid:20086 ppid: 6947 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x3f3/0x880 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103 blkdev_put+0x18/0x130 fs/block_dev.c:1804 blkdev_close+0x1f/0x30 fs/block_dev.c:1853 __fput+0xaa/0x250 fs/file_table.c:281 task_work_run+0x68/0xb0 kernel/task_work.c:135 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:139 [inline] exit_to_user_mode_prepare+0x1e2/0x1f0 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c8a9 Code: Bad RIP value. RSP: 002b:00007f7b1289ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00000000004e8ea0 RCX: 000000000045c8a9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000409 R14: 00000000004c6ae4 R15: 00007f7b1289f6d4 INFO: task syz-executor.0:20114 blocked for more than 144 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:14320 pid:20114 ppid: 6947 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x3f3/0x880 kernel/sched/core.c:4527 schedule+0x37/0xe0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103 __blkdev_get+0xf2/0x730 fs/block_dev.c:1492 blkdev_get+0xf/0x30 fs/block_dev.c:1639 do_dentry_open+0x15a/0x3c0 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x47d/0xa90 fs/namei.c:3368 do_filp_open+0x8e/0x100 fs/namei.c:3395 do_sys_openat2+0x219/0x2d0 fs/open.c:1168 do_sys_open+0x46/0x80 fs/open.c:1184 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x416621 Code: Bad RIP value. RSP: 002b:00007f7b1287d7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000416621 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f7b1287d850 RBP: 000000000078bfa0 R08: 000000000000000f R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000c0f R14: 00000000004ce41d R15: 00007f7b1287e6d4 Showing all locks held in the system: 1 lock held by khungtaskd/1194: #0: ffffffff842f5ac0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x17a kernel/locking/lockdep.c:5826 1 lock held by systemd-journal/3911: #0: ffff88812c02dbd8 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline] #0: ffff88812c02dbd8 (&rq->lock){-.-.}-{2:2}, at: __schedule+0xfa/0x880 kernel/sched/core.c:4445 1 lock held by in:imklog/6352: #0: ffff88812a93e4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x45/0x50 fs/file.c:930 1 lock held by systemd-udevd/8215: #0: ffff88811e789980 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0x46/0x220 fs/block_dev.c:1771 1 lock held by systemd-udevd/8219: #0: ffff88811e78ba00 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0x46/0x220 fs/block_dev.c:1771 1 lock held by systemd-udevd/8233: #0: ffff88811e75b9c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0x46/0x220 fs/block_dev.c:1771 1 lock held by systemd-udevd/8302: #0: ffff88811e7558c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0x46/0x220 fs/block_dev.c:1771 1 lock held by systemd-udevd/8306: #0: ffff88811e7893c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0xf2/0x730 fs/block_dev.c:1492 1 lock held by systemd-udevd/8311: #0: ffff88811e751240 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0xf2/0x730 fs/block_dev.c:1492 1 lock held by syz-executor.4/20055: #0: ffff88811e7893c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x18/0x130 fs/block_dev.c:1804 1 lock held by syz-executor.4/20077: #0: ffff88811e7893c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0xf2/0x730 fs/block_dev.c:1492 1 lock held by syz-executor.0/20086: #0: ffff88811e751240 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x18/0x130 fs/block_dev.c:1804 1 lock held by syz-executor.0/20114: #0: ffff88811e751240 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0xf2/0x730 fs/block_dev.c:1492 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1194 Comm: khungtaskd Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xb3/0xec lib/dump_stack.c:118 nmi_cpu_backtrace.cold.8+0x3e/0x58 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xd5/0xec lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0x58e/0x680 kernel/hung_task.c:295 kthread+0x148/0x170 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60